<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        ul,li{
            margin: 0;
        }
    </style>
    <script src="../js/jquery-1.11.3.js"></script>
    <script>


        $(function(){
            var lis = $('.a').css('color','red');
            console.log(lis);
        })



    </script>
</head>
<body>
<li>aaa</li>
<li id="nav2">aaa2</li>
<h1 class="a b">bbb</h1>
<p class="a">ccccc</p>

</body>
</html>